The present invention is drawn to a process for regenerating a spent catalyst used in the upgrading of heavy hydrocarbon feedstocks and, more particularly, a process for regenerating a spent natural iron base catalyst.
In processing heavy hydrocarbon feedstocks for upgrading same into usable distillates, natural catalysts of laterite, limonite and bauxite type have been widely used. Generally in hydrocracking processes for upgrading these heavy hydrocarbon feedstocks catalysts are added in quantities ranging from 5 to 10% by weight with respect to the feedstock. After the hydrocracking process it is necessary to separate the spent catalyst from the processed hydrocracked product. The waste catalyst from the separation stage contains up to 35 wt.% carbon, up to 30 wt.% sulfur and from about 1.0 to 1.5 wt.% vanadium. Heretofore, the waste catalyst generally cannot be used in any other processing stages for upgrading heavy crude and therefore must be considered as a disposable product. In a commercial plant for hydrocracking heavy hydrocarbon feedstocks in which 100,000 barrels of feedstock are processed a day, approximately 800 tons per day of waste catalyst is produced. The problems associated with handling the volume of waste catalyst produced are numerous. These problems include the costs for transporting and storing of the waste catalysts. However, a more serious and more important problem results from the fact that the catalysts used in the hydrocracking process, as noted above, are naturally occurring catalysts which have limited known reserves.
In light of the foregoing, it would be highly desirable to provide an efficient process for regenerating the spent natural catalysts used in the upgrading of heavy hydrocarbon feedstocks in the hydrocracking process of same. In addition, it would be extremely efficient to develop a process for regenerating spent natural catalysts wherein the regenerated catalysts could again be employed with the hydrocracking process for upgrading heavy hydrocarbon feedstocks.
Accordingly, it is a principal object of the present invention to develop a process for the regeneration of a spent natural catalyst used in upgrading heavy hydrocarbon feedstocks.
It is a particular object of the present invention to provide a process as aforesaid wherein the regenerated spent catalysts have physical and structural characteristics similar to the virgin natural catalyst.
It is a further object of the present invention to provide a process as aforesaid wherein the regenerated catalyst has an activity in treating heavy hydrocarbon feedstocks similar to that obtained with a virgin catalyst.
It is a still further object of the present invention to provide a process as aforesaid which is economical and highly efficient.
Further objects and advantages will appear hereinbelow.